Radiosignaling



April 12, 1927.

RADIOS IGNALING File d Sent. 28. 1921 c. s. AGATE ET AL 2 Sheets-Shoot 1 f'mm mmfral/ed dance ilillllr iillllli /a mad gnwnboz (51ml & IW-WRLANS C. S. AGATE ET AL RADIOSIGNALING April 12; 1927. 1,624,201

Filed ,Sent. 28, 1921 2 Sheets-Sheet 2 f0 recorder avweutoz (LSAGATE (J "W' WILLANS Patented Apr. 12, 1927.

'UNITED STATES PATENT OFFICE.

CHARLTON STANFORD AGATE, OF CHELIIIS'FURD, AND PETER WILLIAM WILLANS, OF

LONDON, ENGLAND, ASSIGNORS TO RADIO CORPORATION OF AMERICA, A COR- PORATION OF DELAWARE.

RADIOSIGNALING.

Application filed September 28, 1921, Serial No.

This invention relates to means for controlling electric currents and for detecting Or recording radio signals.

According to this invention two oscilla tor-y circuits tuned to the same frequency are maintained in oscillation, and are coupled to an untuned circuit. The latter circuit preferably consists of two coils one coupled to each oscillatory circuit or oscillator, and connected in series and across the filament and grid of a thermionic valve operating as a rectifier. The coupling of the third circuit to each of the oscillators should be close, while the coupling between the two oscillators should be as small as possible. In the anode circuit of the valve may be included an electro-magnetic relay or other device according to the purpose for which the invention is to be used. The valve is preferably arranged to work at a point on its characteristic where the grid current is small or Zero. With such an arrangement it is found that the reaction of the current in the third circuit upon the oscillators is very small. WVhen one or both of the oscillators is detuned in any way there is a consid'erable change of oscillating potential on the grid of the valve in the third circuit, which gives rise to a correspondingly considerable change in the anode current of this valve, which change in current is capable of actuating a relay, recorder or the like.

The invention is illustrated by the accompanying diagrams, in whiclt1,:-

Fig. 1 is anillustration of an arrangement of circuits embodying the invention.

Figs. 2, 3 and 4 are illustrations of other embodiments of the invention.

Referring to Figure 1 Aand B are two oscillation circuitsin which. oscillations are maintained by thermionic valves or according to any well known method, for example by the three electrode tube oscillation generators A, B with suitable circuits. The third. circuit consists of two inductances, I D, closely coupled to circuits A and B, and connected in series with the grid and filament ot a three electrode valve E arranged-to operate as a rectifier. he circuit C is arranged to be well below resonance for the frequency of the oscillators, and a grid battery F is inserted and adjusted to prevent the flow of grid current. The

503,797, and in Great Britain October 12, 1,920.

current in the third circuit is thus vanishingly small.

It is found that if A and B are tuned to exact resonance i. e. to the point in which no beats occur in circuit C, a very slight disturbance of the resonance conditions in either A or B gives rise to aconsiderable change of oscillating potential on the grid of the valve E which on rectification yields a corresponding change of direct current through a relay or galvanometer G, which may be advantageously connected in the plate circuit of valve E. I

The apparatus may be employed for the purpose of controlling electric currents used for various purposes or recording radiosignals by making the controlling agency or the signal throw one or other of the circuits A and B out of tune. I

The change in tuning may be accomplished in various ways, for instance, the arrangement shown in conjunction with Fig. 1 may be employed. Here a small auxiliary condenser R is shown connected in parallel to the condenser E of circuit A as shown it consists of two plates Hand I in close proximity to each other, one of which (H) is arranged to be susceptible of small mechanical displacements, for example, by means of a small electrosniagnet 0 connected to a controlling agency. The plate H may be attached to or cooperate with any apparatus by whose motion it is desired to operatethe relay G. Such an arrangement is particularly advantageous when it is desirable to avoid electrical contacts or to reduce the mechanical load on such apparatus.

For the purpose of recording radio signals an. arrangement of the type shown in Figure 1 may be employed. The plate H is in this case a vibrating reed energized by the electromagnet O. Thevibrating reed may be either aperiodic, i. e. of the nature of a telephone diaphragm, or it may be arranged to have a natural frequency corresponding to the note frequency oi. the signals, selective recording being thus possible. The recorder will be connected .to the relay contacts. In either case a telephone may be inserted in addition to or in place of the relay.

If- H and I are each capable ofdisplacement along the same path and it is desired to make the mechanism to which H is attached hunt the mechanism to which I is attached this can be effected by arranging that I is driven, r example, by a motor G under the control of the relay G, the motor being provided with a cam tor actuating the plate I. This feature is illustrated in dotted lines on Fig. 1. The frequency of the circuit A and therefore the capacity between the plates H and I is thus lcept constant and the plate H will hunt the plate I ithout touching it or putting any appreciable load upon it.

Instead of varying the tuning by a condenser the inductance of circuit A may be varied by a small niechanimll displacement, say, of a varionieter.

Since the frequency of oscillations in circuit A in general varies with change of filament brightness in the maintaining valve (such variation being very sharp for suitable values of the components of the circuit) it is possible to operate the relay G by a change in the filament brightness of circuit A, and thus to use the device as a voltage regulator.

In this case the auxiliary condenser E or inductance is not necessary as the controlling agency is the source of E. M. F. such as a current generator 1 (Fig. which is connected to the filament of circuit A. This is maintained constant or controlled by the voltage regulator 2, which is operated by the relay G.

The relay can also be used to maintain the frequency of oscillations of a transmitter constant. This is illustrated in Figure 3. Here the transmitter circuit A takes the place of the circuit A and variations of the frequency of its oscillations are assumed to take place from any cause, say, the swing ing of the aerial in the wind. The circuits B and C are rranged as before, and changes of current through the relay G will talzc place when changes 01'' wave length in A occur. The latter may be corrected by the arrangement shown. K is a variometer coil connected to circuit A. and pivoted about a point K. The coil is attached to a lever l to the ends of which are attached the cores of two solenoids M, M, it necessary dashpots N, N may be attached to these cores to damp the motion of the variometer. The relay G has a neutral position and energizes one or other of the solenoids ac cording as the current rises or falls. The connections can be so arranged that this change of current produces an adjustment of the variometer coil K tending to counteract the change of wave length. Careful screening of circuit B from the direct influence oil A is desirable. It the oscillations of A are not continuous but are broken up as in signaling advantage can be taken of the fact that it is possible to adjust the apparatus so that the relay current is the same whether the transmitter is inoperative or oscillating at its correct wave length.

Another method of recording continuous wave signals consists in superimposing the high frequency signals upon the oscillations of A which will be tuned to approximately the same frequency. An effect is thereby obtained in circuit C as it the frequency of awave changed. This superimposition may be effected by coupling the source oi signals i. e. the aerial or the amplifier) electrostatic-ally or cle-tromagnetically to the circuit A, or else by the arrangement shown in Figure 4.. quency signals are applied to the grid and filamentot a valve P the plate and filament of which are connected to the plate and tila ment of the valve A of A. WVith this arrangement the signals cause a change in the relay current which can be used for recording purposes, the selectivity for wave length being very pronounced.

Having now described our invention what we claim is 1. In electrical controlling or indicating circuits, the combination or two oscillatory circuits tuned to the same frequency, means for maintaining oscillations therein, a current actuated controlling agency for chang ing the magnitude of the current in one of said oscillation circuits, an untuned circuit coupled to the two circuits and a relay actuated by currents in this third circuit to control or indicate changes in the controlling agency.

2. In electrical controlling or indicating circuits, the combination of two oscillatory circuits normally tuned to the same frequency, means for maintaining oscillations therein, a. current actuated controlling agency for changing the magnitude of the current in one of said oscillation circuits, a third circuit coupled to the two circuits, means adapted to modify the currents of one of the first mentioned circuits and a relay actuated by currents in the third circuit to control or indicate changes in the controlling agency.

1n electrical controlling or indicating circuits, the combination of two oscillatory circuits normally tuned to the same frequency, means for maintaining oscillations therein, a current actuated controlling agency for changing the magnitude of the current in one of said oscillation circuits, a third circuit coupled to the two circuits, means adapted to change the tuning of one of the first mentioned circuits and a relay actuated by currents in the third circuit to control or indicate changes in the controlling agency.

4. In electrical controlling or indicating circuits, the combination of two oscillatory circuits normally tuned to the same frequency, means for maintaining oscillations .l-lere the amplified high iretherein, a current actuated controlling agency for changing the magnitude of the current in one of said oscillation circuits, a third circuit coupled to the two circuits, a thermionic valve connected in said third circuit and a relay connected in the plate filament circuit of said valve to control or indicate changes in the controlling agency.

5. In electrical controlling or indicating circuits, the combination of two oscillatory circuits normally tuned to the same frequency, means for maintaining oscillations therein, a current actuated controlling agency for changing the magnitude of the current in one of said oscillation circuits, means for modifying the currents in one of the first mentioned circuits, at third circuit coupled to the two circuits, a thermionic valve connected in said third circuit and a relay connected in the plate filament circuit of said valve to control or indicate changes in the controlling agency.

6. In electrical controlling or indicating circuits, the combination of two oscillatory circuits normally tuned to the same frequency, means for maintaining oscillations therein, a current actuated controlling agency for changing the magnitude of the current in one of said oscillation circuits, means adapted to change the tuning of one of the first mentioned circuits, a third circuit coupled to the two circuits, a thermionic valve connected in said third circuit and a relay connected in the plate filament circuit of said valve to control or indicate changes Y in the controlling agency.

7. In electrical controlling or indicating circuits, the combination of two oscillatory circuits tuned to the same frequency, a variable impedance in circuit with the main tuning elements of one of said circuits, means for maintaining oscillations in each of said circuits, an untuned circuit coupled to the two circuits, current-actuated controlling means cooperating with said variable impedance and a relay actuated by currents in the third circuit.

8. In electrical controlling or indicating circuits, the combination of two oscillatory circuits tuned to the same frequency, a variable condenser in circuit with the main tuning elements of one of said circuits, means for maintaining oscillations in each of said circuits, an untuned circuit coupled to the,

two circuits, current-actuated controlling means cooperating with said variable condenser and a relay .actuated by currents in the third circuit.

9. In electrical controlling or recording circuits, the combination oftwo oscillatory circuits tuned to the same frequency, a variable condenser in circuit with the main tuning elements of one of said circuits, said condenser having two movable plates, means for maintaining oscillations in eachof said circuits, an untuned circuit coupled to the two circuits, a relay actuated by currents in the untuned circuit and means cooperating with said relay for causing one plate of the variable condenser to hunt the other plate.

CHARLTON STANFORD AGATE. PETER WILLIAM WILLANS. 

